President Joe Biden accidentally calls Vice President Kamala Harris 'first lady'

United States President Joe Biden accidentally referred to Vice President Kamala Harris as the first lady, sparking laughter.

Biden's slip of the tongue occurred during an event on Equal Pay Day on Tuesday, when he was explaining Harris was unable to attend the event as her husband Doug Emhoff had COVID-19. Watch in the video above.

"There's been a little change in arrangement of who is on the stage because of the first lady's husband contracting COVID-19," Biden said.

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It was only after someone from the audience pointed out what he had said — implying accidentally that he himself had contracted COVID-19 — did Biden realise his mistake and correct himself.

Event attendees started laughing, and the president joked about the gaffe.

"That's right, she's fine," Biden said as he gestured to his wife, First Lady Jill Biden, who was there with him.

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"Second lady — the first gentleman, how about that?" he said.

"I'm Joe Biden. I'm Jill Biden's husband and proud of it."

Biden then used his speech to call for equal pay for women, and also signed an executive order encouraging the government of the United States to consider banning federal contractors from searching for information regarding the previous salaries of job applicants.

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It was confirmed by the White House that Second Gentleman Doug Emhoff — who has been married to Vice President Harris since 2014 — had tested positive to COVID-19, and that at that time, Harris herself had tested negative.

Emhoff's diagnosis comes after seven House Democrats tested positive for the coronavirus after attending a party in Philadelphia on the weekend.

On Sunday, former president Barack Obama revealed he had tested positive to COVID-19, but his wife, former first lady Michelle Obama, had tested negative.